Fathom out: biogeographical subdivision across the Western Australian continental margin – a multispecies modelling approach
Biogeographical regions are often used as a basis for management strate-
gies, yet a challenge for biodiversity management across broad scales is estab-
lishing biogeographical regions that are robust across taxonomic groups.
Finite mixture models were developed to predict multiple species
assemblages termed archetypes. Modelled species archetypes were developed
using Decapoda, Ophiuroidea and Polychaeta species, which were grouped
based on their similar responses to oceanographic and geographical gradients.
Outer-shelf and slope (50–1200 m) of the continental margin of Western Australia (~11°S–36°S).
Four faunal regions were defined based on cross-taxa surrogates
grouped as archetypes. These faunal regions were defined by oxygen, salinity,
carbon and temperature gradients across latitude and bathymetry. Two broad
latitudinal bands and two bathyal regions were described. Adjacent faunal
groups were not defined by abrupt geographical breaks but rather transitions.
Main conclusions
These results suggest that faunal distributions were less
finely resolved than existing marine bioregions on the Western Australian con-
tinental margin and that environmental gradients are correlated with distribu-
tions of benthic marine invertebrates. Identifying biogeographical regions based
on these methods has the potential to inform management across a broad
range of environments.
Document type: